The Core Center Grant for Balance Research at the University of Pittsburgh consists of two Cores, an Animal Vestibular Neurophysiology Core (AVNC) and a Human Virtual Reality Core (HVRC). These Cores will serve both basic scientists and clinical investigators who perform research related to balance function using animal models, normal human subjects, and patients with balance disorders. The overall goal of the two research cores for which support is requested is to foster collaborative research activities in an efficient and cost-effective manner among a group of independently-funded investigators, each of whom studies some aspect of balance function or dysfunction. The Animal Vestibular Neurophysiology Core (AVNC) will consist of two separate facilities capable of delivering precise, computer-controlled, vestibular stimulation to awake behaving mammals including subhuman primates. These facilities are fully equipped for producing natural vestibular stimuli and recording various responses, including the firing of isolated single neurons. The AVNC facility will support the synergistic and collaborative research activities of several existing laboratories whose equipment is currently in heavy use. This Core will allow additional new experiments that go beyond the capabilities of the existing individual laboratories. The HVRC will consist of a projection-based immersive environment that allows control of the entire visual field, including the floor, of upright research subjects. Objective subject monitoring capabilities include video oculography-based binocular eye position, six degree-of-freedom head movement monitoring, motion analysis, ground reaction forces measured by a force plate, heart rate, and blood pressure. This Core will be used extensively to assess the influence of visual stimuli on upright balance in normal human subjects and patients with balance disorders. The facility will foster collaborative interactions among investigators with various backgrounds including bioengineering, biomechanics, physical therapy, neurology, and psychiatry. The two proposed research Cores will occupy 1110 square feet in the Otolaryngology Research Center on the first floor of the Eye and Ear Institute. The Core Grant Director, Associate Director, and Research Core Directors will provide management of the resources in the Cores to assure appropriate data quality and resource allocation.